1. Field
Aspects of embodiments of the present invention relate to a rechargeable battery having flexibility.
2. Description of the Related Art
With the technological development of mobile devices, a demand for rechargeable batteries as an energy source has increased. A rechargeable battery is a battery which is designed to repeatedly perform charging and discharging operations, unlike a primary battery.
Small-capacity rechargeable batteries may be used in small portable electronic devices such as mobile phones, laptop computers, and camcorders.
Large-capacity rechargeable batteries may be used as power supplies for driving motors for hybrid vehicles and electric vehicles.
For example, a rechargeable battery may include an electrode assembly which performs charging and discharging operations, a pouch which accommodates the electrode assembly, and an electrode tab which extends from the electrode assembly outside the pouch. This pouch-type rechargeable battery may be configured to have a stacked electrode assembly and an electrolyte solution embedded in the pouch.
A stacked electrode assembly is arranged by repeatedly stacking an anode, a separator, a cathode, and a separator and has electrode tabs that extend to the outside of the pouch. The electrode tabs are welded to uncoated regions of the cathode and the anode.
When a bending stress is applied to the stacked electrode assembly, a curvature radius of an inner surface of the bent electrode assembly is reduced by ½ of a thickness and thus a length thereof is reduced in a ½ inner region of the thickness, such that the inner surface of the bent electrode assembly is contracted.
To the contrary, a curvature radius of an outer surface of the electrode assembly is increased by ½ of a thickness and thus a length thereof is increased in a ½ outer region of the thickness, such that the outer surface of the electrode assembly is expanded.
Accordingly, the rechargeable battery is deformed.
Even though the bending stress is applied to the pouch type rechargeable battery, the rechargeable battery is not bent by the desired curvature, and therefore, for the rechargeable battery to be bent at the desired curvature, a very large bending stress needs to be applied to the rechargeable battery.
In this case, when the bending stress beyond a threshold stress is applied to the pouch type rechargeable battery, the rechargeable battery may be fractured and a short-circuit may occur in the rechargeable battery.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form prior art.